A Multi-Scale Hybrid CFD-DEM-PBM Description of a Fluid-Bed Granulation Process

Abstract

In this study, a hybrid multi-scale model has been developed for a continuous fluid bed wet granulation process by dynamically coupling computational fluid dynamics (CFD) with a discrete element model (DEM) and population balance model (PBM). In this process, the granules are formed by spraying the liquid binder on the fluidized powder bed. The fluid flow field has been solved implementing CFD principles and the behavior of the solid particles has been modeled using DEM techniques whereas the change in particle size has been quantified with the help of PBM. The liquid binder droplets have been modeled implicitly in DEM. A detailed understanding of the process aids in the development of better design, optimization and control strategies. The model predicts the evolution of important process variables (i.e., average particle diameter, particle size distribution (PSD) and particle liquid content) over time, which have qualitative similarity with experimentally observed trends. The advantage of incorporating the multi-scale approach is that the model can be used to study the distributions of collision frequencies, particle velocity and particle liquid content in different sections of the fluid bed granulator (FBG), in a more mechanistic manner.

A Review of Dynamic Models of Hot-Melt Extrusion

“…Figure 23 presents an example (see [136]) of a good combination between these two methods to determine particle physical characteristics. Moreover, computational fluid dynamics (CFD) can also be coupled to PBM-DEM to model particle-fluid interactions in fluidized bed granulation [137][138][139]. However, conversely to the previously-introduced methods, PBM-DEM describes only the variations of particle physical properties (assuming the whole device in the steady state) as the granule size distribution (GSD), the moisture content, etc.…”

New Biosorbent Materials: Selectivity and Bioengineering Insights

“…However, some changes in the symbols and the physical meanings differentiate the models and give other potential to the whole engineering part. Models are used everywhere for simulating any possible process [54][55][56][57][58][59][60][61][62][63][64][65][66]. The main models, which will be discussed in following, are the Freundlich, Langmuir, and Langmuir-Freundlich (L-F) equations.…”

A reduced order PBM–ANN model of a multi-scale PBM–DEM description of a wet granulation process

“…Wang et al (2012) similarly utilizes DEM to obtain collision and dissipation energies during the granule breakage processes in a ball milling operation to link with PBM. Other coupled models have investigated coupling PBM and DEM with Computational Fluid Dynamics (CFD) for particle-fluid interactions in fluidized bed granulation processes (Rajniak et al, 2009;Fries et al, 2011;Sen et al, 2014).…”